TDA7297 Build Guide

JDUBS · « **Reply #140 on:** 21 Apr 2015, 09:06 pm »

Quote from: Salis Audio on 21 Apr 2015, 04:37 am

10kohm is about as low as you can get. Alternatively you can use a buffer between them.

Yeah, 10k is as low as I've seen to...but is it the ideal value here (I've got one on hand, that's why I ask)? No buffer in between.

-Jim

gdaniel · « **Reply #141 on:** 7 May 2015, 05:23 pm »

Hello, I would like to ask for some help.

I bought a TDA7297 amplifier (http://www.banggood.com/ACDC-12V-2-x-15W-TDA7297-Version-B-Digital-Audio-Amplifier-Board-p-917242.html) and I tried 3 different power source (DC) and I got no bass.

I tried with
5V DC 1A (USB), no noise, but no bass
12V DC 12A (XBOX360 PSU), big noise, no bass
8.5V DC 1.5A (Camera charger), big noise, no bass.

Could you help me Guys why I have a crap sound quality? I read everywhere this amplifier have good sound quality , but not for me.

Thanks!

Folsom · « **Reply #142 on:** 9 May 2015, 04:50 am »

You need bigger input capacitors. Try 1uf film caps. 12v will the better.

gychang · « **Reply #143 on:** 9 May 2015, 01:44 pm »

Quote from: gdaniel on 7 May 2015, 05:23 pm

Hello, I would like to ask for some help.

I bought a TDA7297 amplifier (http://www.banggood.com/ACDC-12V-2-x-15W-TDA7297-Version-B-Digital-Audio-Amplifier-Board-p-917242.html) and I tried 3 different power source (DC) and I got no bass.

I tried with
5V DC 1A (USB), no noise, but no bass
12V DC 12A (XBOX360 PSU), big noise, no bass
8.5V DC 1.5A (Camera charger), big noise, no bass.

Could you help me Guys why I have a crap sound quality? I read everywhere this amplifier have good sound quality , but not for me.

Thanks!

Had a similar prob, cured with astron linear power supply.

Folsom · « **Reply #144 on:** 9 May 2015, 07:36 pm »

Quote from: gychang on 9 May 2015, 01:44 pm

Had a similar prob, cured with astron linear power supply.

That's a great solution, but the input capacitors will give you bass down to 20hz, as opposed starting to roll over prematurely. The stats say it can do -3db at 20hz, but not with .22uf capacitors on the input.

DizRotus · « **Reply #145 on:** 28 Jul 2015, 02:42 am »

I've read that TDA7297 is balanced, as opposed to single-ended. I've also read that the inputs share a common ground. This seems to be contradictory, unless I understand "balanced" even less than I thought.

My Pono player plays modified (no common ground) headphones in balanced mode. I'm concerned that using Pono as a balanced source for this amp might harm the Pono player. Any insights are appreciated.

gychang · « **Reply #146 on:** 12 Jun 2016, 01:26 am »

Quote from: rhing on 28 Dec 2013, 03:02 am

I removed the diodes and installed solid core Copper wire jumpers in their place. The improvements in frequency extension, better dynamic response and detail were subtle, but worth the effort. If anyone has this amp and has a decent DC power supply, this is a worthwhile mod.

I have removed the pot and will like to use just as a power amp (always at maximal gain), I plan to use it with moode audio software which include a volume control. What connection or mod is needed?

Folsom · « **Reply #147 on:** 12 Jun 2016, 01:46 am »

I would check build guide V.2

gychang · « **Reply #148 on:** 12 Jun 2016, 02:31 am »

Quote from: Folsom on 12 Jun 2016, 01:46 am

I would check build guide V.2

checked the V.2 but did not catch how to fix the gain... I still have some parts from the first version..., plan to try V.2 in near future. Good stuff.

Folsom · « **Reply #149 on:** 12 Jun 2016, 02:45 am »

The gain is always fixed. The pot is just volume.

gychang · « **Reply #150 on:** 12 Jun 2016, 03:22 am »

Quote from: Folsom on 12 Jun 2016, 02:45 am

The gain is always fixed. The pot is just volume.

with the pot removed will it function at full volume, and allow the input device, i.e. iphone to lower volume?

Folsom · « **Reply #151 on:** 12 Jun 2016, 03:48 am »

moremoremore · « **Reply #152 on:** 12 Jun 2016, 10:36 am »

Thanks, Jeremy. I think you broke the record for speedy shipping. I'm looking forward to building this out semi-deluxe, or at least slowly.

Sakujin · « **Reply #153 on:** 20 Dec 2016, 11:02 am »

Quote from: Folsom on 15 Dec 2013, 09:27 pm

Alright guys, here it is! First the parts you need. *C4 amended.

From Mouser.

Input caps, order 10x because it's cheaper than 4x (yes you'll need 4x)

647-UES1H010MDM
UES1H010MDM
50volts 1uF

Power cap 1x

661-EKZH250E222MK30S
EKZH250ELL222MK30S
25Volts 2200uF

Shunt/Mute Power cap

661-EKY500ETC220ME1
EKY-500ETC220ME11D
50volts 22uF

Building

Ok, so first I recommend getting to this point, the naked board of all the parts you don't need. That is unless you want the volume pot, but I wouldn't recommend it.

Here's a clear board, I've labeled the R and L inputs, and their grounds. R1, D1, D2, C1, C2, C3, C4 (not shown removed) C5, CN4, and RP 50k have been removed.

Install a wire for the bypass of the diode (D2), I did this on the bottom.

Install the Shunt/Mute cap (C3) 22uf, negative side (short lead) goes to the striped pattern on the board.

Install the upside C1 and C2 capacitors, 1uf Nichicon Muse. Long leads go toward the input (as circled)

Install on the bottom 1uf capacitors with the reverse orientation of the first two (long leads towards the chip), on C1 and C2. This is very important, and can only be done with non-polar caps. Without doing this your amplifier won't be that great unless you got some very nice film caps for the inputs.

Install C5, the big 2200uf cap, again stripe to stripes.

That's it! My next post here will be about advanced options, this is the simple, but very good build.

Use only DC power supply after removing the diode.

*do not replace C4, it's a worthless snubber that causes ringing.

So I've removed the pot and the input block and now I dont understand how I can feed it audio signal. I tried to hook up L/R to the corresponding holes on the first picture but no sound would come out, plus im very confused by the terminals you put in the last picture at the pot and line in. Please help.

mboxler · « **Reply #154 on:** 20 Dec 2016, 05:32 pm »

The holes marked L/R are inputs to the pot from what was the input jack. The middle holes are outputs from the pot/inputs to the amp. The left holes are ground.

I would not use the terminal blocks, and solder + to the middle holes and - to the left most holes (ground).

If you want to use terminal blocks, the connections will be more involved.

I assume you have a way to control volume; otherwise, you will be going from no sound to full volume after this connection.

Mike

Folsom · « **Reply #155 on:** 20 Dec 2016, 05:37 pm »

You should be following Ver. 2 also

Sakujin · « **Reply #156 on:** 21 Dec 2016, 03:50 am »

Quote from: mboxler on 20 Dec 2016, 05:32 pm

The holes marked L/R are inputs to the pot from what was the input jack. The middle holes are outputs from the pot/inputs to the amp. The left holes are ground.

I would not use the terminal blocks, and solder + to the middle holes and - to the left most holes (ground).

If you want to use terminal blocks, the connections will be more involved.

I assume you have a way to control volume; otherwise, you will be going from no sound to full volume after this connection.

Mike

Ok thanks, I'll try this later on.

Quote from: Folsom on 20 Dec 2016, 05:37 pm

You should be following Ver. 2 also

I would but it has to wait since there are no reasonable priced part shop in Norway, I have to gather up a chunky list for mouser.com and order everything in one go. I've also ordered 5 more of these amps plus I have a bunch of salvaged caps from old sony mini hifi system/cd walkman etc which I want to compare to the non modded ver.

gychang · « **Reply #157 on:** 19 Aug 2017, 09:02 pm »

I have successfully modded version 1 in past without removing the pot and input source socket. This time I wanted to remove the pot and input socket, otherwise standard mod of version 1.

I get no audio output, replacing the amp works fine, when I turn off the power source to the amp, I get a soft click and LED indicated getting power. I have attached the input socket as pictured. Can someone spot where my mistake may be?
thanks

Folsom · « **Reply #158 on:** 20 Aug 2017, 01:57 am »

Picture makes it a little hard to tell. It appears like you need to jumper where the pot was for left and right channels.

gychang · « **Reply #159 on:** 20 Aug 2017, 02:40 am »

Quote from: Folsom on 20 Aug 2017, 01:57 am

Picture makes it a little hard to tell. It appears like you need to jumper where the pot was for left and right channels.

is this correct, to jump the red line?

thanks